Comparison of the Effect of Noise on Cortical Responses Evoked by Sound Onset and Acoustic Changes

Objectives: Previous research has demonstrated the impact of noise on cortical potentials triggered by acoustic alterations and sound onsets. This study investigated the effects of noise type and stimulus characteristics on cortical responses to sound onset and acoustic changes. Materials and Methods: Twenty participants (ten women and ten men) with normal hearing between the ages of 24 and 33 had their auditory cortex N1 responses (onset and acoustic change provoked) recorded at +10 dB signal-to-noise ratio in both quiet and two distinct noise types. Results: White noise had smaller onset amplitudes than quiet, and both white and speech noise conditions had longer latencies. Speech noise reduced the amplitudes of the acoustic changes, but it had no effect on the latencies. Only the onset latencies of both noises were lengthened when /iu/ was used. When comparing responses to the two stimuli under the same conditions, /ui/ exhibited longer latencies than /iu/ only in the quiet environment; in the other situations, /ui/ and /iu/ latencies and amplitudes were identical. The acoustic change reactions for /ui/ and /iu/ were only similar in terms of latencies in loud environments. When the sound onset and acoustic change responses were compared in the same setting, the amplitudes were lower, and the latencies were higher for both stimuli in all conditions. Conclusion: The influence of noise varies based on the stimuli, responses to acoustic changes induced by the sound, and the type of noise utilized. Future studies should further examine the effects of various noise types on onset and acoustic change responses, particularly in individuals with speech discrimination difficulties.